Why don't Tokamaks blow up whenever they lose confinement?

I haven't been able to find an answer to this anywhere. Suppose there's a quench in a coil at a tokamak and confinement is lost. I understand that there is no longer anything keeping the fusion going, but it seems to me that the plasma should still have enough inertia that, however momentarily, fusion would continue occurring, and the whole thing would go off like an h-bomb. Obviously this doesn't happen. Why?